This invention relates to apparatus for extracting milk, and more particularly, to breast pumps which are convenient and comfortable to use.
Pumps for expressing milk from breasts are well-known. One known breast pump is disclosed in Whittlestone U.S. Pat. No. 4,607,596.
The Whittlestone patent discloses a breast pump having two milk collectors connected to a pump which applies both a vacuum and pulsating pressure to the breasts to extract milk. The pulsating pressure reciprocates between positive and negative (vacuum) pressure. The pulsating pressure gently massages and compresses the breasts to stimulate milk production, and the vacuum secures the milk collectors to the breasts and helps draw the milk and collect it. The pulsating pressure actually cyclically increases the vacuum level at the breast(s), which further stimulates milk production. However, the pressure is not relieved during pulsation in the Whittlestone patent, so pressure can build to a level sufficient to stall a small motor in a well-sealed system. In addition, the amplitude of the pressure pulses can be reduced by pressure build-up, which is also undesirable. Thus, there is a need for breast pumps that use pulsation as well as vacuum to draw milk, and have controlled relief of the pressure during operation.
In the Whittlestone device, milk from the two collectors is commonly drawn into a first collection vessel, and then a second collection vessel. The milk is drawn through vacuum lines, though, which makes cleaning difficult. Accordingly, there is a need for breast pumps which are more sanitary and easier to clean than the Whittlestone device.
The Whittlestone patent discloses a breast cup having a housing, a relatively soft inner ring or donut, and a flexible liner. The liner wraps around the outlet of the cup, and a bung is inserted into the cup outlet to pass the vacuum and milk. At the inlet side, the liner is simply folded over the outside of the housing. This design has limitations. The liner is not accurately aligned and reliably sealed on the inlet side, so moisture and other contaminants can get inside the liner, which is undesirable. At the outlet, the nipple can contact the bung and the liner can collapse around the breast, which can be uncomfortable, and can cause unnecessary trauma, including potential abrasion at the tip of the nipple. Accordingly, there is a need for breast pumps having cups which better fix the liner to the housing. There is also a need for breast pump cups which protect at least the end of the nipple from discomfort due to pulsating pressure.
The breast pump disclosed in the Whittlestone patent is a diaphragm pump operated by an electric motor. Rotation of the motor shaft is translated into back and forth action by a somewhat large and cumbersome linkage which moves the diaphragm. This adds not only size but weight to the pump, as well. Moreover, the motor must be fairly large, in part because a high vacuum is needed for cleaning purposes, and to maintain adequate vacuum and pressure if the system is leaky. These are problems because convenient storage and portability are desirable to breast pump users. Thus, there is a need for breast pumps which are lighter and smaller than known devices.
Accordingly, one object of this invention is to provide new and improved apparatus for extracting milk from breasts.
Another object is to provide new and improved breast pumps which are more convenient and comfortable to use.
Another object is to provide new and improved breast pumps that use both vacuum and pulsation pressure to collect milk, and control the pulsation pressure to maintain consistent, predetermined increases in the vacuum as the milk is collected.
Still a further object is to provide new and improved breast pumps which are more sanitary, easy to clean and easy to disassemble and re-assemble in the field.
Yet another object is to provide new and improved breast pumps which are relatively light, compact and portable.
A device for expressing milk from one or both breasts has at least one milk collector and a pump. Preferably, the device has first and second collectors (also called expressers), so that both breasts can be milked simultaneously. Each expresser has a cup assembly which fits on the breast, a pulsation port to which a supply of pressurized pulsating air is connected, and a vacuum port to which a vacuum supply is connected. The pulsating air and vacuum are created by the pump. In use, pulsating air causes massage and gentle compression of the breast and stimulates milk production, while the vacuum secures a liner in the collector on the breast and expresses the milk from the breast. Among other things, the pressure pulses increase the vacuum at the breast.
Both vacuum and pulsating air pressure are fairly well controlled by adequately sealing the various parts of the device and providing a pressure release vent for the pressurized air supply to each expresser. A vacuum adjustment is also provided.
The collectors also include a cap and manifold which direct the vacuum and pressure, a cup assembly which is preferably press fit onto the manifold, a collection vessel secured to the bottom of the manifold, and, if desired, a one-way check valve or the like between the manifold and the collection vessel. After passing through the vacuum adjustment, the vacuum is directed through the cap and manifold, collection vessel and cup assembly so that the milk is drawn into the collector with little or no milk entering the vacuum lines to the pump. A filter may be provided for added isolation of the vacuum pump and vacuum lines, if desired.
The cup assembly includes a bell housing, a relatively soft donut shaped pad, and the flexible liner, preferably made of silicone, nitrile or other suitable material that meets requirements for medical materials. The liner is secured to the inlet side of the cup assembly by a locking type of attachment, and extends around the bottom or lower end of the bell housing, where it is secured by another locking press fit configuration.
The bottom end of the cup assembly fits into a receptacle in the manifold. The receptacle has a hollow boss which extends into the cup assembly by a desired distance. The hollow portion inside the boss increases the area for extension of the nipple during milk expression, avoiding potentially uncomfortable contact at the nipple area. The boss also prevents the liner from collapsing around the end of the nipple during use, and keeps the throat of the cup assembly open for milk flow.
The collector can be easily disassembled and cleaned in a dishwasher or the like, by removing the collection vessel and using or storing the milk, removing the cap and then removing the cup assembly. The cup assembly can be cleaned without removing the liner, if desired, or the liner can be removed and cleaned separately, or replaced. A cleaning cap can be placed over the air pulsation port of the cup assembly when the cup assembly is cleaned in its assembled condition, to prevent water from entering the space between the liner and the bell housing. A valve could be used in place of the cap for this purpose, if desired.
The manifold, cap and valve can also be washed. The cup assembly can be easily reassembled after cleaning by reinserting the cup assembly in the manifold, re-attaching the cap to the manifold and cup assembly, and securing another collection vessel to the bottom of the manifold, with or without the check valve.
The pump includes a movable diaphragm in a chamber. The diaphragm is oscillated back and forth by a relatively small linear actuator device such as a stepper motor. The motor preferably is a self-contained system that moves its final object axially. The motor can have a shaft which does not rotate, but moves back and forth axially. The shaft of the motor is directly or nearly directly linked to the diaphragm, which eliminates complex and cumbersome linkage components, reducing the size and weight of the pump.